Mixed Pneumocystis and Cryptococcus cutaneous infection histologically mimicking xanthoma.

Cutaneous Pneumocystis jirovecii infection is rare. It is thought that the disease emerges from a latent infection delivered via hematogenous and/or lymphatic dissemination from a primary lung infection in immunocompromised individuals. A 32-year-old human immunodeficiency virus-positive male was admitted for headache and vomiting. He was diagnosed with meningitis due to Cryptococcus neoformans and sputum tested positive for Pneumocystis. Six months later, he presented with a slightly crusted yellowish brown plaque and 2 similar but smaller papules with telangiectasia near the right angle of the mouth. Biopsy of the area featured histiocytes expanded by foamy cytoplasm as in a xanthoma except that the vacuoles were coarser. Special stains ultimately demonstrated the characteristic disks of Pneumocystis accompanied by a minor component of budding yeasts (Cryptococcus) in the same fields. This case illustrates the utility of adequate special stains in recognizing a mixed cutaneous infection, particularly in human immunodeficiency virus-positive patients, when microscopy presents an odd xanthoma-like lesion.

Increased diagnosis of thin superficial spreading melanomas: A 20-year study.

BACKGROUND: Diagnostic practice by dermatopathologists evaluating pigmented lesions may have evolved over time. OBJECTIVES: We sought to investigate diagnostic drift among a group of dermatopathologists asked to re-evaluate cases initially diagnosed 20 years ago. METHODS: Twenty nine cases of dysplastic nevi with severe atypia and 11 cases of thin radial growth-phase melanoma from 1988 through 1990 were retrieved from the pathology files of the Massachusetts General Hospital. All dermatopathologists who had rendered an original diagnosis for any of the 40 slides and the current faculty in the Massachusetts General Hospital Dermatopathology Unit were invited to evaluate the slide set in 2008 through 2009. RESULTS: The mean number of melanoma diagnoses by the 9 study participants was 18, an increase from the original 11 melanoma diagnoses. A majority agreed with the original diagnosis of melanoma in all 11 cases. In contrast, a majority of current raters diagnosed melanoma in 4 of the 29 cases originally reported as dysplastic nevus with severe atypia. Interrater agreement over time was excellent (kappa 0.88) and fair (kappa 0.47) for cases originally diagnosed as melanoma and severely atypical dysplastic nevus, respectively. LIMITATIONS: The unbalanced composition of the slide set, lack of access to clinical or demographic information, access to only one diagnostic slide, and imposed dichotomous categorization of tumors were limitations. CONCLUSIONS: A selected cohort of dermatopathologists demonstrated a general trend toward the reclassification of prior nonmalignant diagnoses of severely atypical dysplastic nevi as malignant but did not tend to revise prior diagnoses of cutaneous melanoma as benign.

A histological examination for skin atrophy after 6 months of treatment with fluocinolone acetonide 0.01%, hydroquinone 4%, and tretinoin 0.05% cream.

Melasma is a common disorder affecting a significant percentage of the population, particularly those with skin of color. Therapy with hydroquinone, a depigmenting agent, as a single agent or in combination with other agents has been used with variable success. A triple-combination (TC) cream combining hydroquinone 4% with tretinoin 0.05% and fluocinolone acetonide 0.01% was developed for the treatment of melasma. We studied the use of TC cream for 24 weeks and had tissue samples for all time points in 62 patients with moderate to severe melasma. The atrophogenic potential of TC cream was evaluated through serial histopathologic examination of skin biopsies. No statistically significant histopathologic signs of atrophy of the epidermis or dermis were noted at any time point throughout the study. There was a marked reduction in epidermal melanin in treated subjects; however, we did not observe any significant difference in baseline and treated samples in the amount of perivascular inflammatory infiltrate, dermal mucin, keratinocyte and melanocyte atypia, or mast cells, consistent with findings of previous studies where topical retinoids were used. An increase in the mean number of blood vessels per square millimeter of tissue was observed in 2 study cohorts between baseline and week 24. These results suggest that the risk of skin atrophy with 24-week use of TC cream for the treatment of melasma is very low.